Test Code 0232728
C2 Complement, Functional, with Reflex, Serum

Additional Codes

Performing Laboratory

Useful For

Investigation of a patient with a low (absent) hemolytic
complement (CH50), with reflex testing to C3 and C4, if
appropriate

Testing Algorithm

If the C2 result is less than 15 U/mL, then complement C3 and C4
will be performed at an additional charge.

Method Name

Automated Liposome Lysis Assay

Reporting Name

C2 Complement,Functional,w/Reflex,S

Specimen Type

Serum Red

Advisory Information

This test is for assessment of complement C2 and includes
assessment of C3 and C4 as reflex testing. Unless a deficiency has
already been identified, initial assessment should begin with the
total complement assay (COM / Complement, Total, Serum), which is a
screen for suspected complement deficiencies and should be
performed before ordering individual complement component assays. A
deficiency of an individual component of the complement cascade
will result in an undetectable total complement level.

Specimen Required

Patient Preparation: Fasting preferred but not
required

Supplies: Aliquot Tube, 5 mL (T465)

Collection Container/Tube: Red top

Submission
Container/Tube: Plastic, 5-mL tube

Specimen Volume: 1 mL

Collection Instructions:

1. Immediately after specimen collection, place the tube on wet
ice.

2. Centrifuge and separate serum from clot.

3. Immediately freeze specimen.

CentraCare Laboratory Services
Note:

Freeze serum within 30 minutes of collection and submit frozen.

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type

Temperature

Time

Serum Red

Frozen

21 days

Reject Due To

Hemolysis

Mild OK; Gross OK

Lipemia

Mild OK; Gross reject

Icterus

Mild OK; Gross OK

Other

Serum gel tube

Reference Values

25-47 U/mL

Interpretation

Low levels of complement may be due to inherited deficiencies,
acquired deficiencies, or due to complement consumption (eg, as a
consequence of infectious or autoimmune processes).

Absent (or low) C2 levels in the presence of normal C3 and C4
values are consistent with a C2 deficiency.

Low C2 levels in the presence of low C3 and C4 values are
consistent with a complement-consumptive process.

Low C2 and C4 values, in the presence of normal values for C3 is
suggestive of C1 esterase inhibitor deficiency.

Day(s) and Time(s) Performed

Monday through Saturday; 3 p.m.

Analytic Time

Same day/1 day

Specimen Retention Time

14 days

Test Classification

This test was developed and its performance characteristics
determined by Mayo Clinic in a manner consistent with CLIA
requirements. This test has not been cleared or approved by the
U.S. Food and Drug Administration.